In image storage products, large-capacity optical disks such as Blu-ray Discs or HD DVDs are realized as next-generation large-capacity DVDs that are larger in capacity than the current DVDs and capable of recording high-definition images for long hours, and then, the progress is made toward the high-definition images of packaged media. Moreover, in parallel with those, there are also movements to commence extending and/or shifting toward sales by download distribution from the sales schemes of DVDs conventionally provided by package sales. For the time being, the next-generation DVD of high definition may mainly exert sales by packaged media because of an enormous amount of data volume, and meanwhile, the download distribution heads mainly toward cultivating a new market due to extension of distribution channels for DVD contents (the content that is authored complying with the DVD format) of standard definition.
Due to the movements described above, it is required that a plurality of contents each conventionally accommodated in one DVD is allowed to be collectively accommodated in a next-generation large-capacity optical disk. In addition, distribution schemes include download distribution in which a DVD content is downloaded to a user so as to be directly recorded into a recordable large-capacity optical disk at home, and in a packaged supply in which a package is produced to accommodate a plurality of DVD contents in a large-capacity optical disk on the side of a content provider so as to be supplied, and a technology that can be applied to both the schemes is required to be put into practical use.
Under these circumstances, importance to be placed on in particular is copyright protection of the contents. When download distribution is performed by way of a network, a threat leading to an unauthorized copy of contents increases, so that technological countermeasures to this are required more than before.
Conventionally, as for DVD formats, an ISO/IEC Standard that is an international standard, and an ECMA Standard that has been the source thereof are known (for example, refer to Non-Patent Document 1, Non-Patent Document 2). In addition, in relation to image recording, a technology to record and/or reproduce image data including navigation data into/from a recording medium (for example, refer to Patent Document 1) and a copyright management system of contents (for example, refer to Patent Document 2) are known.
As a disk format technology for a next-generation large-capacity optical disk, an error-correction cluster configuration method (for example, refer to Patent Document 3), a technology to efficiently record and/or play back a transport stream when an image file is recorded into a disk (for example, refer to Patent Document 4), and a technology to transform at high speed by correlating a transport stream with a program stream using a relational expression (for example, refer to Patent Document 5) are known.
In addition, as technologies to perform download distribution of an image contents by way of a network, a technology in which download processing is performed by letting a content server send a download control file to the receiving side (for example, refer to Patent Document 6), and a management system of copyrights of contents (for example, refer to Patent Document 7) are known.
[Non-Patent Document 1] ISO/IEC 16448
[Non-Patent Document 2] ECMA-267
[Patent Document 1] Japanese Laid-Open Patent Publication No. H08-273304
[Patent Document 2] Japanese Laid-Open Patent Re-Publication WO97/14147
[Patent Document 3] Japanese Laid-Open Patent Publication No. 2003-123392
[Patent Document 4] Japanese Laid-Open Patent Publication No. 2001-167528
[Patent Document 5] Japanese Laid-Open Patent Publication No. 2005-513936
[Patent Document 6] Japanese Laid-Open Patent Publication No. 2005-159703
[Patent Document 7] Japanese Laid-Open Patent Publication No. 2005-092830